Permalink
Fetching contributors…
Cannot retrieve contributors at this time
159 lines (136 sloc) 3.22 KB
/* -*- linux-c -*- ------------------------------------------------------- *
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright 2007 rPath, Inc. - All Rights Reserved
*
* This file is part of the Linux kernel, and is made available under
* the terms of the GNU General Public License version 2.
*
* ----------------------------------------------------------------------- */
/*
* Simple command-line parser for early boot.
*/
#include "boot.h"
static inline int myisspace(u8 c)
{
return c <= ' '; /* Close enough approximation */
}
/*
* Find a non-boolean option, that is, "option=argument". In accordance
* with standard Linux practice, if this option is repeated, this returns
* the last instance on the command line.
*
* Returns the length of the argument (regardless of if it was
* truncated to fit in the buffer), or -1 on not found.
*/
int __cmdline_find_option(unsigned long cmdline_ptr, const char *option, char *buffer, int bufsize)
{
addr_t cptr;
char c;
int len = -1;
const char *opptr = NULL;
char *bufptr = buffer;
enum {
st_wordstart, /* Start of word/after whitespace */
st_wordcmp, /* Comparing this word */
st_wordskip, /* Miscompare, skip */
st_bufcpy /* Copying this to buffer */
} state = st_wordstart;
if (!cmdline_ptr)
return -1; /* No command line */
cptr = cmdline_ptr & 0xf;
set_fs(cmdline_ptr >> 4);
while (cptr < 0x10000 && (c = rdfs8(cptr++))) {
switch (state) {
case st_wordstart:
if (myisspace(c))
break;
/* else */
state = st_wordcmp;
opptr = option;
/* fall through */
case st_wordcmp:
if (c == '=' && !*opptr) {
len = 0;
bufptr = buffer;
state = st_bufcpy;
} else if (myisspace(c)) {
state = st_wordstart;
} else if (c != *opptr++) {
state = st_wordskip;
}
break;
case st_wordskip:
if (myisspace(c))
state = st_wordstart;
break;
case st_bufcpy:
if (myisspace(c)) {
state = st_wordstart;
} else {
if (len < bufsize-1)
*bufptr++ = c;
len++;
}
break;
}
}
if (bufsize)
*bufptr = '\0';
return len;
}
/*
* Find a boolean option (like quiet,noapic,nosmp....)
*
* Returns the position of that option (starts counting with 1)
* or 0 on not found
*/
int __cmdline_find_option_bool(unsigned long cmdline_ptr, const char *option)
{
addr_t cptr;
char c;
int pos = 0, wstart = 0;
const char *opptr = NULL;
enum {
st_wordstart, /* Start of word/after whitespace */
st_wordcmp, /* Comparing this word */
st_wordskip, /* Miscompare, skip */
} state = st_wordstart;
if (!cmdline_ptr)
return -1; /* No command line */
cptr = cmdline_ptr & 0xf;
set_fs(cmdline_ptr >> 4);
while (cptr < 0x10000) {
c = rdfs8(cptr++);
pos++;
switch (state) {
case st_wordstart:
if (!c)
return 0;
else if (myisspace(c))
break;
state = st_wordcmp;
opptr = option;
wstart = pos;
/* fall through */
case st_wordcmp:
if (!*opptr)
if (!c || myisspace(c))
return wstart;
else
state = st_wordskip;
else if (!c)
return 0;
else if (c != *opptr++)
state = st_wordskip;
break;
case st_wordskip:
if (!c)
return 0;
else if (myisspace(c))
state = st_wordstart;
break;
}
}
return 0; /* Buffer overrun */
}